The $5 billion valuation would be equivalent to about $625 per square foot. If the stake sells, it would likely become the second most expensive real estate sale in Downtown, behind the $3.2 billion World Trade Center in 2001.

Along with partner Urban American Management, Brookfield is also considering the sale of the 4,000-unit multifamily package known as the Putnam portfolio. Sources familiar with a recent appraisal said it could be worth about $1.5 billion.

At Brookfield Property Partners’ most recent earnings call, the firm’s CEO Bryan Kingston alluded to further asset sales and said “core real estate in the U.S. continues to be a pretty desirable place for a lot of these offshore sovereign wealth funds.”